The present invention relates to a device, which makes it possible to guide the placing of dental implants, which usage involves completely novel concepts, rendering remarkable advantages over the systems known in the art.
Dental implant is an ancient art through which missing dental pieces are replaced, and it is a solution that man found long time ago. In effect, even during Egyptian times attempts were made to replace dental pieces for scoured pieces, fitted immediately after the original piece was removed.
Since those times, many improvements have been made, including the development of prosthesis and bridges to replace missing pieces.
Likewise, osseointegration process has been studied and developed for the last twenty-five years. In this process, several materials suitable for implantation in jawbones without bone-rejection have been developed and tested. One of the materials tested that resulted to be relatively successful is titanium and alloys from it. With these materials, screw-shaped pieces have been fabricated, the pieces being screwed in the bone after a hole is drilled for fitting said screw. But in practice there is a percentage of rejections, the reason for many of which is lack of planning, and this is troublesome for the patient and also causes a deep feeling of frustration for the dentist applying said surgical practice.
Continuous, deep study of the foregoing drawbacks encountered in implants resulted in the confirmation that it was extremely important to determine the exact place where the hole must be drilled on the maxilla bone (hereinafter referred to as incidence point), and the tilt thereof (hereinafter referred to as incidence angle). For this purpose, different radiographic tests have been used in order to studyxe2x80x94prior to any surgeryxe2x80x94all special parameters of the maxilla bone of each patient, so as to minimize rejection risks. Said radiographic tests include panoramic x-ray, which provide a complete view of maxilla and teeth.
However the use of these x-ray plates provides a first approach to study the morphology of the jaw bone of the patient to be implanted, in practice they result to be insufficient, as any radiography implies a flat image and also presents a certain deformation from actual sizes, which is a drawback for suitable anchoring of the implant as it prevents specifying the accurate position or coordinates for the implant. Said deformation of actual image varies upon the equipment used, but in most cases it leads to a deformation ranging form 20 to 50%, which is clearly unacceptable for practicing a high precision surgery.
As already mentioned, another important issue to be taken into account is the tilt of the hole where the implant is placed. This tilt is directly related to characteristics of the jaw bone where in implant is placed, which changes from one patient to another, and from one tooth to another in the same patient; so in each case the incidence angle must be accurately specified, so as to be sure that neither proximate cavities nor nerves would result injured, causing an irreparable damage for the patient.
The device and method of this invention have been developed for overcoming the foregoing drawbacks, the use of which allows for a completely accurate placing of the implant. For this method, a computed tomography is necessary, or either any other radio-diagnostic test which, along with the use of a planning device, renders a template with correct incidence points and angles.
Through computed tomography, axial and transversal cross sections may be observed, as well as panoramic views of the patient""s mouth, all of them without deformation, so the profile of the jaw bone where the implant is to be placed is clearly seen.
On its side, by using the device of the present invention, it is possible to exactly specify the tilt that must be considered for each implant, using the information provided by said tomography. The whole process shall be taught hereinafter.
The use of the proposed device and method implies several improvements, which may be summarized as follows:
1) a correct planning of the implant is achieved, which reduces to a minimum any risk associated to surgery;
2) in most cases, an unexposed surgery is favored, which results completely non-bloody for the patient, and the post-surgery stage is almost unnoticed;
3) in case the patient has an irregular jaw bone and gum tissue must be cut and lifted for working over the jaw bone, the method is also useful for keeping planning constant throughout surgery;
4) it greatly reduces time spent in the surgical setting;
5) by using the method, the implant is more safely distributed, and positioning results more accurate, which undoubtedly facilitates the job of the restorative dentist when fabricating the prosthesis;
6) having a highly accurate tool for this type of surgeries, negligence or unskillfullness, which are frequent in today dental implant practice, are almost negligible.
One of the main objects of the proposed device is to obtain a plate, called xe2x80x9csurgical templatexe2x80x9d, which is useful for transferring the planning into a patient mouth, and said planning is kept constant during surgery, so exploratory surgeries in the maxilla having so many vital elements, are avoided.
Said surgical template defines a guide which provides the professional with exact incidence angle and point where the hole is to be drilled, for further anchoring the implant.
Basically, the device of the present invention allows for the preparation of a pre-tomographic guide with radio opaque elements, so as to have a full, accurate view of the computed tomography details and the surgical template, which will be placed into the patient when he/she is subject to surgery.
Moreover, this invention provides a method, which basically comprises the following stages:
1) preparing a pre-tomographic guide with an impression (mouth model), through which a plasterxe2x80x94or similar material""model of the patient mouth is made, and also a diagnostic replica piece (a scale model of the prosthesis). By using a traditional duplicator, a reproduction of the replica piece is made in a polymer material, such as acrylic or any other like transparent material; also the knot of a polymeric material, such as acrylic or the like, may be employed; the replica is placed in said model and with a specially designed device holes are drilled at the position of each dental piece, measuring the incidence angle both, mesio-distal and mouth-palatine/lingual, the values being logged in a sheet. A radio opaque substance is introduced in each hole, thus determining pre-tomography guide;
2) taking a computer tomography with the patient having the pre-tomographic guide in his mouth;
3) making a computer-assisted planning with a specially designed software (which is a surgery simulator), with which it is possible to see tomographic cross sections of the maxilla bone, and over them a white line corresponding to the radio opaque substance of the guide where we have registered the estimated incidence angles, incidence angle and incidence point are rectified, and new values are logged;
4) making a surgical template (which serves for transferring the planning with corrections into the patient""s mouth), using the aforementioned device, which allows for metal guides be placed over an acrylic plate in all positions where each implant will be placed, having corrected incidence angle and point;
5) placing the template obtained in step 4) into the patient mouth, and placing the implant following the steps already known for this process.
This means that the drill is inserted into the metal guides already mentioned, so the hole in the patient jaw bone has the predetermined incidence point and tilt with the above advantages.
In fact, the features and improvements mentioned above are only a few of the characteristics of the present invention, which will be more clearly understood as the present description proceeds, when taken in conjunction with the accompanying drawings, which are merely exemplary of the invention, and not limitative in any way.